Lafora progressive myoclonus epilepsy (LD) is a fatal autosomal recessive neurodegenerative disorder characterized by the presence of glycogen-like intracellular inclusions called Lafora bodies. LD is caused by mutations in two genes, EPM2A and EPM2B, encoding respectively laforin, a dual-specificity protein phosphatase, and malin, an E3 ubiquitin ligase. Previously, we and others have suggested that the interactions between laforin and PTG (a regulatory subunit of type 1 protein phosphatase) and between laforin and malin are critical in the pathogenesis of LD. Here, we show that the laforin-malin complex downregulates PTG-induced glycogen synthesis in FTO2B hepatoma cells through a mechanism involving ubiquitination and degradation of PTG. Furthermore, we demonstrate that the interaction between laforin and malin is a regulated process that is modulated by the AMP-activated protein kinase (AMPK). These findings provide further insights into the critical role of the laforin-malin complex in the control of glycogen metabolism and unravel a novel link between the energy sensor AMPK and glycogen metabolism. These data advance our understanding of the functional role of laforin and malin, which hopefully will facilitate the development of appropriate LD therapies.

Collagen, as the major structural protein of the extracellular matrix in animals, is a versatile biomaterial of great interest in various engineering applications. Electrospun nanofibers of collagen are regarded as very promising materials for tissue engineering applications because they can reproduce the morphology of the natural bone but have as a drawback a poor structural consistency in wet conditions. In this paper, a comparative study between the performance of different cross-linking methods such as a milder enzymatic treatment procedure using transglutaminase, the use of N-[3-(dimethylamino)propyl]-N'-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide, and genipin, and the use of a physical method based on exposure to ultraviolet light was carried out. The chemical and enzymatic treatments provided, in this order, excellent consistency, morphology, cross-linking degree, and osteoblast viability for the collagen nanofibers. Interestingly, the enzymatically cross-linked collagen mats, which are considered to be a more biological treatment, promoted adequate cell adhesion, making the biomaterial biocompatible and with an adequate degree of porosity for cell seeding and in-growth.

R5/PTG is one of the glycogen targeting subunits of type 1 protein phosphatase, a master regulator of glycogen synthesis. R5/PTG recruits the phosphatase to the places where glycogen synthesis occurs, allowing the activation of glycogen synthase and the inactivation of glycogen phosphorylase, thus increasing glycogen synthesis and decreasing its degradation. In this report, we show that the activity of R5/PTG is regulated by AMP-activated protein kinase (AMPK). We demonstrate that AMPK interacts physically with R5/PTG and modifies its basal phosphorylation status. We have also mapped the major phosphorylation sites of R5/PTG by mass spectrometry analysis, observing that phosphorylation of Ser-8 and Ser-268 increased upon activation of AMPK. We have recently described that the activity of R5/PTG is down-regulated by the laforin-malin complex, composed of a dual specificity phosphatase (laforin) and an E3-ubiquitin ligase (malin). We now demonstrate that phosphorylation of R5/PTG at Ser-8 by AMPK accelerates its laforin/ malin-dependent ubiquitination and subsequent proteasomal degradation, which results in a decrease of its glycogenic activity. Thus, our results define a novel role of AMPK in glycogen homeostasis.Glycogen homeostasis depends mainly on the activity of the enzymes involved in its synthesis (glycogen synthase (GS) 2 ) and its degradation (glycogen phosphorylase). These activities are regulated by a complex mechanism involving both allosteric regulation and phosphorylation (1, 2). Interestingly, although there are several kinases (AMPK, PKA, CKI, and glycogen synthase kinase 3) that inhibit glycogen synthesis through the phosphorylation of GS, there is only one known phosphatase (type 1 protein phosphatase (PP1)) that dephosphorylates both GS (leading to its activation) and glycogen phosphorylase (leading to its inactivation), which results in glycogen accumulation (1, 2). PP1 is recruited to glycogen by a family of glycogen targeting proteins, including: G M , G L , R5/PTG, R6, and R3E (3-7). The regulation of the activity of the holoenzyme formed by the PP1 catalytic subunit and one of these glycogen targeting subunits is different in each case. The glycogenic activity of G M is down-regulated by its PKA-dependent phosphorylation; PKA phosphorylates G M at a site in its PP1 binding motif, which leads to its dissociation from PP1. The glycogenic activity of the G L -PP1c holoenzyme is down-regulated by an allosteric mechanism involving phosphorylase-a (8 -10). Little is known about the regulation of the holoenzymes involving R6 or R3E, but in the case of R5/PTG, we and others have recently described that its glycogenic activity is down-regulated by the laforin-malin complex, composed of a dual specificity phosphatase (laforin) and an E3-ubiquitin ligase (malin), which recognizes and ubiquitinates R5/PTG and targets it for proteasomal-dependent degradation (11-13). Laforin and malin are two key proteins related to Lafora disease (LD, OMIM 254780), an autosomal recessive neurodegenerative disorder c...

Background Early microbial colonization is a relevant aspect in human health. Altered microbial colonization patterns have been linked to an increased risk of non-communicable diseases (NCDs). Advances in understanding host-microbe interactions highlight the pivotal role of maternal microbiota on infant health programming. This birth cohort is aimed to characterize the maternal microbes transferred to neonates during the first 1000 days of life, as well as to identify the potential host and environmental factors, such as gestational age, mode of delivery, maternal/infant diet, and exposure to antibiotics, which affect early microbial colonization. Methods MAMI is a prospective mother-infant birth cohort in the Spanish-Mediterranean area. Mothers were enrolled at the end of pregnancy and families were follow-up during the first years of life. Maternal-infant biological samples were collected at several time points from birth to 24 months of life. Clinical and anthropometric characteristics and dietary information is available. Specific qPCR and 16S rRNA gene sequencing as well as short chain fatty acid (SCFAs) profile would be obtained. Multivariable models will be used to identy associations between microbiota and clinical and anthropometric data controlling for confounders. MAMI would contribute to a better understanding of the interaction between diet, microbiota and host response in early life health programming, enabling new applications in the field of personalized nutrition and medicine. Trial registration The study is registered on the ClinicalTrial.gov platform NCT03552939. (June 12, 2018).

The purpose of this study was to generate ultrathin fibers based on polylactide (PLA) biopolyester with antimicrobial controlled release capacity to treat bacterial infections. To achieve this objective, gentamicin antibiotic was encapsulated into pure PLA fibers, a blend of PLA–collagen and coaxial fibers containing a skin of PLA and a core of collagen using the electrospinning technique. The morphology of the gentamicin‐loaded fibers and the antibiotic distribution within the fibers were examined by SEM and TEM. The drug delivery profile of the different electrospun fibers was analyzed using a spectrophotometric method. The performance for treating common possible post‐surgical infections was investigated against Staphylococcus epidermis, Pseudomonas aeruginosa and Escherichia coli. The morphology of the electrospun fibers as well as the hydrophilicity of the polymer blends ultimately determined the antibiotic release characteristics. The results indicated that such drug‐loaded fibers can serve as advanced delivery platforms with strong and timing controllable antibacterial properties.

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